When using an artificial leg, an amputee adapts his body movements to accommodate the characteristics of the components used in the prosthesis. This is done in such a way as to give the most desirable combination of motion, comfort and energy expenditure. Thus the body movements and gait of the amputee are directly related to the characteristics of the components used in the prosthesis. It follows therefore that by changing the characteristic of the components used in the prosthesis the gait of the amputee can be affected.
U.S. Pat. No. 4,547,913 (Phillips, assigned to Flex Foot Inc) describes a composite prosthetic foot having a leg portion, a foot portion and a heel portion all rigidly joined and all three provided with substantial elastic flexability to provide return of energy absorbed and enable the amputee to engage in sports such as running and playing tennis.